1 /* 2 * arch/powerpc/sysdev/dart_iommu.c 3 * 4 * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation 5 * Copyright (C) 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>, 6 * IBM Corporation 7 * 8 * Based on pSeries_iommu.c: 9 * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation 10 * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation 11 * 12 * Dynamic DMA mapping support, Apple U3, U4 & IBM CPC925 "DART" iommu. 13 * 14 * 15 * This program is free software; you can redistribute it and/or modify 16 * it under the terms of the GNU General Public License as published by 17 * the Free Software Foundation; either version 2 of the License, or 18 * (at your option) any later version. 19 * 20 * This program is distributed in the hope that it will be useful, 21 * but WITHOUT ANY WARRANTY; without even the implied warranty of 22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 23 * GNU General Public License for more details. 24 * 25 * You should have received a copy of the GNU General Public License 26 * along with this program; if not, write to the Free Software 27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 28 */ 29 30 #include <linux/init.h> 31 #include <linux/types.h> 32 #include <linux/mm.h> 33 #include <linux/spinlock.h> 34 #include <linux/string.h> 35 #include <linux/pci.h> 36 #include <linux/dma-mapping.h> 37 #include <linux/vmalloc.h> 38 #include <linux/suspend.h> 39 #include <linux/memblock.h> 40 #include <linux/gfp.h> 41 #include <asm/io.h> 42 #include <asm/prom.h> 43 #include <asm/iommu.h> 44 #include <asm/pci-bridge.h> 45 #include <asm/machdep.h> 46 #include <asm/cacheflush.h> 47 #include <asm/ppc-pci.h> 48 49 #include "dart.h" 50 51 /* Physical base address and size of the DART table */ 52 unsigned long dart_tablebase; /* exported to htab_initialize */ 53 static unsigned long dart_tablesize; 54 55 /* Virtual base address of the DART table */ 56 static u32 *dart_vbase; 57 #ifdef CONFIG_PM 58 static u32 *dart_copy; 59 #endif 60 61 /* Mapped base address for the dart */ 62 static unsigned int __iomem *dart; 63 64 /* Dummy val that entries are set to when unused */ 65 static unsigned int dart_emptyval; 66 67 static struct iommu_table iommu_table_dart; 68 static int iommu_table_dart_inited; 69 static int dart_dirty; 70 static int dart_is_u4; 71 72 #define DART_U4_BYPASS_BASE 0x8000000000ull 73 74 #define DBG(...) 75 76 static DEFINE_SPINLOCK(invalidate_lock); 77 78 static inline void dart_tlb_invalidate_all(void) 79 { 80 unsigned long l = 0; 81 unsigned int reg, inv_bit; 82 unsigned long limit; 83 unsigned long flags; 84 85 spin_lock_irqsave(&invalidate_lock, flags); 86 87 DBG("dart: flush\n"); 88 89 /* To invalidate the DART, set the DARTCNTL_FLUSHTLB bit in the 90 * control register and wait for it to clear. 91 * 92 * Gotcha: Sometimes, the DART won't detect that the bit gets 93 * set. If so, clear it and set it again. 94 */ 95 96 limit = 0; 97 98 inv_bit = dart_is_u4 ? DART_CNTL_U4_FLUSHTLB : DART_CNTL_U3_FLUSHTLB; 99 retry: 100 l = 0; 101 reg = DART_IN(DART_CNTL); 102 reg |= inv_bit; 103 DART_OUT(DART_CNTL, reg); 104 105 while ((DART_IN(DART_CNTL) & inv_bit) && l < (1L << limit)) 106 l++; 107 if (l == (1L << limit)) { 108 if (limit < 4) { 109 limit++; 110 reg = DART_IN(DART_CNTL); 111 reg &= ~inv_bit; 112 DART_OUT(DART_CNTL, reg); 113 goto retry; 114 } else 115 panic("DART: TLB did not flush after waiting a long " 116 "time. Buggy U3 ?"); 117 } 118 119 spin_unlock_irqrestore(&invalidate_lock, flags); 120 } 121 122 static inline void dart_tlb_invalidate_one(unsigned long bus_rpn) 123 { 124 unsigned int reg; 125 unsigned int l, limit; 126 unsigned long flags; 127 128 spin_lock_irqsave(&invalidate_lock, flags); 129 130 reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE | 131 (bus_rpn & DART_CNTL_U4_IONE_MASK); 132 DART_OUT(DART_CNTL, reg); 133 134 limit = 0; 135 wait_more: 136 l = 0; 137 while ((DART_IN(DART_CNTL) & DART_CNTL_U4_IONE) && l < (1L << limit)) { 138 rmb(); 139 l++; 140 } 141 142 if (l == (1L << limit)) { 143 if (limit < 4) { 144 limit++; 145 goto wait_more; 146 } else 147 panic("DART: TLB did not flush after waiting a long " 148 "time. Buggy U4 ?"); 149 } 150 151 spin_unlock_irqrestore(&invalidate_lock, flags); 152 } 153 154 static void dart_flush(struct iommu_table *tbl) 155 { 156 mb(); 157 if (dart_dirty) { 158 dart_tlb_invalidate_all(); 159 dart_dirty = 0; 160 } 161 } 162 163 static int dart_build(struct iommu_table *tbl, long index, 164 long npages, unsigned long uaddr, 165 enum dma_data_direction direction, 166 struct dma_attrs *attrs) 167 { 168 unsigned int *dp; 169 unsigned int rpn; 170 long l; 171 172 DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr); 173 174 dp = ((unsigned int*)tbl->it_base) + index; 175 176 /* On U3, all memory is contiguous, so we can move this 177 * out of the loop. 178 */ 179 l = npages; 180 while (l--) { 181 rpn = __pa(uaddr) >> DART_PAGE_SHIFT; 182 183 *(dp++) = DARTMAP_VALID | (rpn & DARTMAP_RPNMASK); 184 185 uaddr += DART_PAGE_SIZE; 186 } 187 188 /* make sure all updates have reached memory */ 189 mb(); 190 in_be32((unsigned __iomem *)dp); 191 mb(); 192 193 if (dart_is_u4) { 194 rpn = index; 195 while (npages--) 196 dart_tlb_invalidate_one(rpn++); 197 } else { 198 dart_dirty = 1; 199 } 200 return 0; 201 } 202 203 204 static void dart_free(struct iommu_table *tbl, long index, long npages) 205 { 206 unsigned int *dp; 207 208 /* We don't worry about flushing the TLB cache. The only drawback of 209 * not doing it is that we won't catch buggy device drivers doing 210 * bad DMAs, but then no 32-bit architecture ever does either. 211 */ 212 213 DBG("dart: free at: %lx, %lx\n", index, npages); 214 215 dp = ((unsigned int *)tbl->it_base) + index; 216 217 while (npages--) 218 *(dp++) = dart_emptyval; 219 } 220 221 222 static int __init dart_init(struct device_node *dart_node) 223 { 224 unsigned int i; 225 unsigned long tmp, base, size; 226 struct resource r; 227 228 if (dart_tablebase == 0 || dart_tablesize == 0) { 229 printk(KERN_INFO "DART: table not allocated, using " 230 "direct DMA\n"); 231 return -ENODEV; 232 } 233 234 if (of_address_to_resource(dart_node, 0, &r)) 235 panic("DART: can't get register base ! "); 236 237 /* Make sure nothing from the DART range remains in the CPU cache 238 * from a previous mapping that existed before the kernel took 239 * over 240 */ 241 flush_dcache_phys_range(dart_tablebase, 242 dart_tablebase + dart_tablesize); 243 244 /* Allocate a spare page to map all invalid DART pages. We need to do 245 * that to work around what looks like a problem with the HT bridge 246 * prefetching into invalid pages and corrupting data 247 */ 248 tmp = memblock_alloc(DART_PAGE_SIZE, DART_PAGE_SIZE); 249 dart_emptyval = DARTMAP_VALID | ((tmp >> DART_PAGE_SHIFT) & 250 DARTMAP_RPNMASK); 251 252 /* Map in DART registers */ 253 dart = ioremap(r.start, resource_size(&r)); 254 if (dart == NULL) 255 panic("DART: Cannot map registers!"); 256 257 /* Map in DART table */ 258 dart_vbase = ioremap(__pa(dart_tablebase), dart_tablesize); 259 260 /* Fill initial table */ 261 for (i = 0; i < dart_tablesize/4; i++) 262 dart_vbase[i] = dart_emptyval; 263 264 /* Initialize DART with table base and enable it. */ 265 base = dart_tablebase >> DART_PAGE_SHIFT; 266 size = dart_tablesize >> DART_PAGE_SHIFT; 267 if (dart_is_u4) { 268 size &= DART_SIZE_U4_SIZE_MASK; 269 DART_OUT(DART_BASE_U4, base); 270 DART_OUT(DART_SIZE_U4, size); 271 DART_OUT(DART_CNTL, DART_CNTL_U4_ENABLE); 272 } else { 273 size &= DART_CNTL_U3_SIZE_MASK; 274 DART_OUT(DART_CNTL, 275 DART_CNTL_U3_ENABLE | 276 (base << DART_CNTL_U3_BASE_SHIFT) | 277 (size << DART_CNTL_U3_SIZE_SHIFT)); 278 } 279 280 /* Invalidate DART to get rid of possible stale TLBs */ 281 dart_tlb_invalidate_all(); 282 283 printk(KERN_INFO "DART IOMMU initialized for %s type chipset\n", 284 dart_is_u4 ? "U4" : "U3"); 285 286 return 0; 287 } 288 289 static struct iommu_table_ops iommu_dart_ops = { 290 .set = dart_build, 291 .clear = dart_free, 292 .flush = dart_flush, 293 }; 294 295 static void iommu_table_dart_setup(void) 296 { 297 iommu_table_dart.it_busno = 0; 298 iommu_table_dart.it_offset = 0; 299 /* it_size is in number of entries */ 300 iommu_table_dart.it_size = dart_tablesize / sizeof(u32); 301 iommu_table_dart.it_page_shift = IOMMU_PAGE_SHIFT_4K; 302 303 /* Initialize the common IOMMU code */ 304 iommu_table_dart.it_base = (unsigned long)dart_vbase; 305 iommu_table_dart.it_index = 0; 306 iommu_table_dart.it_blocksize = 1; 307 iommu_table_dart.it_ops = &iommu_dart_ops; 308 iommu_init_table(&iommu_table_dart, -1); 309 310 /* Reserve the last page of the DART to avoid possible prefetch 311 * past the DART mapped area 312 */ 313 set_bit(iommu_table_dart.it_size - 1, iommu_table_dart.it_map); 314 } 315 316 static void pci_dma_dev_setup_dart(struct pci_dev *dev) 317 { 318 if (dart_is_u4) 319 set_dma_offset(&dev->dev, DART_U4_BYPASS_BASE); 320 set_iommu_table_base(&dev->dev, &iommu_table_dart); 321 } 322 323 static void pci_dma_bus_setup_dart(struct pci_bus *bus) 324 { 325 if (!iommu_table_dart_inited) { 326 iommu_table_dart_inited = 1; 327 iommu_table_dart_setup(); 328 } 329 } 330 331 static bool dart_device_on_pcie(struct device *dev) 332 { 333 struct device_node *np = of_node_get(dev->of_node); 334 335 while(np) { 336 if (of_device_is_compatible(np, "U4-pcie") || 337 of_device_is_compatible(np, "u4-pcie")) { 338 of_node_put(np); 339 return true; 340 } 341 np = of_get_next_parent(np); 342 } 343 return false; 344 } 345 346 static int dart_dma_set_mask(struct device *dev, u64 dma_mask) 347 { 348 if (!dev->dma_mask || !dma_supported(dev, dma_mask)) 349 return -EIO; 350 351 /* U4 supports a DART bypass, we use it for 64-bit capable 352 * devices to improve performances. However, that only works 353 * for devices connected to U4 own PCIe interface, not bridged 354 * through hypertransport. We need the device to support at 355 * least 40 bits of addresses. 356 */ 357 if (dart_device_on_pcie(dev) && dma_mask >= DMA_BIT_MASK(40)) { 358 dev_info(dev, "Using 64-bit DMA iommu bypass\n"); 359 set_dma_ops(dev, &dma_direct_ops); 360 } else { 361 dev_info(dev, "Using 32-bit DMA via iommu\n"); 362 set_dma_ops(dev, &dma_iommu_ops); 363 } 364 365 *dev->dma_mask = dma_mask; 366 return 0; 367 } 368 369 void __init iommu_init_early_dart(struct pci_controller_ops *controller_ops) 370 { 371 struct device_node *dn; 372 373 /* Find the DART in the device-tree */ 374 dn = of_find_compatible_node(NULL, "dart", "u3-dart"); 375 if (dn == NULL) { 376 dn = of_find_compatible_node(NULL, "dart", "u4-dart"); 377 if (dn == NULL) 378 return; /* use default direct_dma_ops */ 379 dart_is_u4 = 1; 380 } 381 382 /* Initialize the DART HW */ 383 if (dart_init(dn) != 0) 384 goto bail; 385 386 /* Setup bypass if supported */ 387 if (dart_is_u4) 388 ppc_md.dma_set_mask = dart_dma_set_mask; 389 390 controller_ops->dma_dev_setup = pci_dma_dev_setup_dart; 391 controller_ops->dma_bus_setup = pci_dma_bus_setup_dart; 392 393 /* Setup pci_dma ops */ 394 set_pci_dma_ops(&dma_iommu_ops); 395 return; 396 397 bail: 398 /* If init failed, use direct iommu and null setup functions */ 399 controller_ops->dma_dev_setup = NULL; 400 controller_ops->dma_bus_setup = NULL; 401 402 /* Setup pci_dma ops */ 403 set_pci_dma_ops(&dma_direct_ops); 404 } 405 406 #ifdef CONFIG_PM 407 static void iommu_dart_save(void) 408 { 409 memcpy(dart_copy, dart_vbase, 2*1024*1024); 410 } 411 412 static void iommu_dart_restore(void) 413 { 414 memcpy(dart_vbase, dart_copy, 2*1024*1024); 415 dart_tlb_invalidate_all(); 416 } 417 418 static int __init iommu_init_late_dart(void) 419 { 420 unsigned long tbasepfn; 421 struct page *p; 422 423 /* if no dart table exists then we won't need to save it 424 * and the area has also not been reserved */ 425 if (!dart_tablebase) 426 return 0; 427 428 tbasepfn = __pa(dart_tablebase) >> PAGE_SHIFT; 429 register_nosave_region_late(tbasepfn, 430 tbasepfn + ((1<<24) >> PAGE_SHIFT)); 431 432 /* For suspend we need to copy the dart contents because 433 * it is not part of the regular mapping (see above) and 434 * thus not saved automatically. The memory for this copy 435 * must be allocated early because we need 2 MB. */ 436 p = alloc_pages(GFP_KERNEL, 21 - PAGE_SHIFT); 437 BUG_ON(!p); 438 dart_copy = page_address(p); 439 440 ppc_md.iommu_save = iommu_dart_save; 441 ppc_md.iommu_restore = iommu_dart_restore; 442 443 return 0; 444 } 445 446 late_initcall(iommu_init_late_dart); 447 #endif 448 449 void __init alloc_dart_table(void) 450 { 451 /* Only reserve DART space if machine has more than 1GB of RAM 452 * or if requested with iommu=on on cmdline. 453 * 454 * 1GB of RAM is picked as limit because some default devices 455 * (i.e. Airport Extreme) have 30 bit address range limits. 456 */ 457 458 if (iommu_is_off) 459 return; 460 461 if (!iommu_force_on && memblock_end_of_DRAM() <= 0x40000000ull) 462 return; 463 464 /* 512 pages (2MB) is max DART tablesize. */ 465 dart_tablesize = 1UL << 21; 466 /* 16MB (1 << 24) alignment. We allocate a full 16Mb chuck since we 467 * will blow up an entire large page anyway in the kernel mapping 468 */ 469 dart_tablebase = (unsigned long) 470 __va(memblock_alloc_base(1UL<<24, 1UL<<24, 0x80000000L)); 471 /* 472 * The DART space is later unmapped from the kernel linear mapping and 473 * accessing dart_tablebase during kmemleak scanning will fault. 474 */ 475 kmemleak_no_scan((void *)dart_tablebase); 476 477 printk(KERN_INFO "DART table allocated at: %lx\n", dart_tablebase); 478 } 479